1. Field of the Invention
The present invention relates to a turbo compressor capable of compressing a fluid by a plurality of impellers, and a refrigerator including the turbo compressor.
Priority is claimed on Japanese Patent Application No. 2008-27067, filed Feb. 6, 2008, the content of which is incorporated herein by reference.
2. Description of the Related Art
As refrigerators which cool or freeze objects to be cooled, such as water, a turbo refrigerator or the like including a turbo compressor which compresses and discharges a refrigerant by impellers is known. In a compressor, when a compression ratio increases, the discharge temperature of the compressor becomes high and the volumetric efficiency thereof degrades. Thus, in the turbo compressor included in the above-mentioned turbo refrigerator or the like, a refrigerant may be compressed in a plurality of stages. For example, a turbo compressor which includes two compression stages provided with an impeller and a diffuser and which compresses a refrigerant sequentially in these compression stages is disclosed in Japanese Patent Unexamined Publication No. 2007-177695.
However, when a diffuser with vanes is used, diffuser vanes are arranged in the flow of a refrigerant. Therefore, the refrigerant will collide against the diffuser vanes. Hence, nonuniformity of the flow occurs in a peripheral direction at outlets of the diffuser vanes, and even a small amount of turbulence of the fluid is generated.
The turbo compressor installed in the turbo refrigerator is connected to the condenser which cools and liquefies the compressed refrigerant. For this reason, the turbulence of the fluid which occurs when the refrigerant collides against the diffuser vanes is transmitted to the condenser.
Also, in order to liquefy a refrigerant which has flowed in as gas in the condenser, a wide space into which the refrigerant as gas is filled exists inside the condenser. Accordingly, turbulence of the fluid transmitted to the condenser echoes, and noise are generated.
As such, the turbo refrigerator has a problem in that noise resulting from the transmission of turbulence of the fluid to the condenser, which occurs as the refrigerant collides against the diffuser vane, is generated.